Thanks George, I love macro photography and actually thought about doing exactly that. What about extension tubes, do you have any experience with those?
I'll try to summarize the pros and cons of the three approaches to macro photography, as best as I know: macro lens, close-up lens (add-on), and extension tubes.
- Macro lens (e.g., the Canon 100mm f/2.8 Macro, which I have)
Pros
Sharpest picture, best image quality, especially the 100mm f/2.8 Macro ("spectacular optics," says Ken Rockwell)
Usually good magnification (e.g., 1:1)
Focuses from infinity down to 1:1 in one twist of the focus ring
Easiest to focus, autofocus usually works very well and very fast (bright viewfinder)
Can use the lens for other purposes (good "portrait" lens, for example; reasonably good for sports)
Fairly long working distance (from the front of the lens to the subject) with 100mm or longer
Fairly fast (f/2.8 for the 100mm)
Least vignetting
No flash shadows in most cases
Cons
Expensive--you have to buy another lens
Heavy--you have to carry another lens
No IS available (not that major, as high magnification shots should be done with a tripod or other steady support and/or with flash)
Focal length changes with magnification (at high magnification, the 100mm Macro lens is really less than 100mm)
- Add-on Close-up lenses (e.g., Canon 500D)
Pros
No significant light loss, so they are as "fast" as the lens you put them on (good or bad[:D])
Less expensive than the Macro lens
Much lighter than the Macro lens
Least bulky option (about the thickness of two normal CPL filters stacked
Works on almost any lens (get the largest size and use step-up rings), including IS lenses, though some lenses will work better than others (the 500D is best for lenses in the 70-300mm range; it works very well with the 70-200mm zooms).
Cons
Image quality worse than the other two; may have worse chromatic aberration (color fringes)
Focus range can be very limited, which means magnification is sort of "fixed," though the zoom gives you some choice
500D is more expensive than good third-party (not Canon) extension tubes (and heavier)
Focus can be difficult; you will probably have to use manual focus and/or move the camera to get into the focus range
The cheap close-up lenses (usually come in a kit of 3 or 4) are single-element and will have worse image quality, especially chromatic aberration (color fringes) than the double-element Canon 500D. However, they are the cheapest way to get into macro photography and may be fine for many people. They do have the advantage of various strengths (diopters), which can be stacked for greater magnification. There are sets made by manufacturers like Hoya that seem to be better than the run-of-the mill sets one can find on eBay.
- Extension tubes (e.g., Kenko's latest, which are cheaper than the Canon tubes but work just as well, plus you can get a set of three, versus two Canon tubes)
Pros
Image quality nearly the same as the lens attached to them (a bit less because the image is spread out more)--no CA added
Cheaper than the other two (compared to 500D, not to cheap close-up lenses)
Lighter than the other two (again, compared to the 500D; the cheap close-up lenses may be fairly light)
May work with all lenses, if you get the latest models that can mount EF-S lenses
Longer focus range than close-up lenses (usually--depends upon the set-up)
Can be used for more than close-up shots: put one or more on a long telephoto lens to get a larger image still at a reasonable distance
Cons
LIGHT LOSS--can be significant. Essentially, they spread the image out over a larger area at the sensor (thus, the sensor sees only a portion of the image from the lens). That can dramatically reduce the light intensity. Doing manual exposures with extension tubes can be difficult for the mathematically-challenged, but TTL exposures should be close--you should experiment with exposure compensation, in any case.
Lose focus range--cannot focus at infinity
May be difficult to autofocus (see #1 for why) (the REALLY cheap extension tubes don't have electrical circuits and don't support autofocus OR aperture settings at all--avoid those like the plague)
The effect depends upon the ratio of the tube length to the lens' focal length: they are most effective with short focal length lenses, much less with long lenses
Less depth of focus than basic lens, as you're essentially using a longer focal length.
Rather fragile compared to the other two (some tubes are easily cracked)--look for tubes with metal mounts rather than plastic
Bulkier than close-up lenses if you carry the entire set
Adds to the length of the lens (cheap tubes can be wobbly)
Which is best? Depends upon what you want. (Yes, I know that's a non-answer!) Extension tubes are versatile--I have read of bird photographers who use them with a 500mm lens to enlarge the image of a bird 50-100 ft away. You can use any one, two, or all three of the Kenko (or the cheaper <span style="font-family: Arial,Helvetica,sans-serif;"]Good News:
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]1.) Spectacular optics!
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]2.) Super sharp.
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]3.) No distortion.
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]4.) Super-fast focusing.
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]5.) Goes to 1:1 in one twist.
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]6.) I'll say it again: spectacular optics!
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]Bad News:
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]None. This is a great lens!
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]I love this lens. It does everything well and has no weak points.
<p style="padding-left: 30px;" align="left"]<span style="font-family: Arial,Helvetica,sans-serif;"]It's
hard to convey this in writing. This is one of those lenses that works
so well, efficiently and effortlessly you wonder why all lenses can't
be this good.
<p align="left"]Bryan is almost as effusive in his review (http://www.adorama.com/MCAETEOS.html?searchinfo=canon%20extension%20tube& item_no=1]Pro Optic set from Adorama) set to get various magnifications. (Just remember that, the longer the tubes, the more the light loss.) The close-up lenses are the most convenient to use: I don't even bother taking off the UV filter. The macro lens has the best image quality, continuous focus, and is the fastest (well, except for my 100mm f/2 with the 500D).
The 100mm f/2.8 Macro lens is, well, spectacular--see Ken Rockwell's review:
<p style="padding-left: 30px;):
<p align="left"]"
The Canon EF 100mm f/2.8 USM Macro Lens is an excellent macro lens - and may be Canon's most fun per dollar lens.
This is the lens I most frequently recommend for someone starting out in macro photography."
<p align="left"]The 180mm L Macro lens has a longer working distance, but not
significantly better image quality and is a LOT more expensive--$1300
vs $490 at B&H; it's also almost a stop slower--f/3.5 vs f/2.8. The non-Canon macro lenses (Sigma 105mm f/2.8; Tamron 90mm f/2.8; Tokina 100mm f/2.8) are almost as expensive as the Canon 100mm f/2.8 and probably not as good. I wouldn't bother with the shorter macro lenses (50mm, 60mm, much less the Tokin 35mm!) because their working distance will be much less for the same magnification. Their only advantage would be longer depth of focus.
<p align="left"]Note that I didn't mention the "macro" zoom lenses. They have the "pro" of being cheaper (maybe) and more versatile than a true macro lens, but at the expense of lower image quality and slower maximum apertures, plus few go to 1:1--the better ones go down to 1:2.
<p align="left"]So, what do I do? Depends. (Another non-answer!) When I'm doing nature photography and want to be prepared for anything, I carry a Think Tank Speed Racer ("http://www.thinktankphoto.com/ttp_product_SpdRcr.php) belt bag or Rotation 360 ("http://www.rotation360.com/) backpack with the 30D & BG-E2 grip, 17-85mm IS, 100-400mm L IS, Sigma 10-20mm, and the 100mm Macro, plus a 1.4x teleconverter and do-dads. (I may add a 580EX flash in a Think Tank pouch.) If I want to lighten the load, I can leave the 100mm Macro home and take the 77mm 500D close-up lens and a 67-77mm step-up ring (which is really there all the time so that I need carry only 77mm filters). When I'm shooting horse shows, I take the 30D + grip and 17-85mm IS (I want to get the 17-55mm f/2.8 IS) plus a smaller bag (e.g., Think Thank Change Up ("http://www.thinktankphoto.com/ttp_product_ChngUp.php)) with a 70-200mm f/2.8L IS, 580EX, and either an Optura 50 camcorder or 85mm f/1.8 and 50mm f/1.8 stacked, especially if it's indoors or in a covered arena. I may throw in the 500D in case I find something interesting.
<p align="left"]That brings me to two other points. First, you'll want to use some sort of stable support for many shots. Shooting
at macro magnifications means a shallow depth of focus, so it can be
hard to hold the camera in focus. To prevent blurring from camera
shake, you'll have to use a fairly fast shutter speed, which means
wider aperture and shallow depth of focus. A good support will help
both. Another factor is that, very often, your subject will be quite
low, including right on the ground. There are many options: tripods
that can get close to the ground and/or can "bend over" to shoot at low
objects, mini-tripods (the best I've found is the Gorillapod Focus,
but, with a ballhead, it's heavy and bulky), "ground pods"
(sleds/frames to which you can attach a ballhead), bean bags, etc.
<p align="left"]Second, in a lot of macro photography, you'll want to use flash. That has two benefits: more light allows you to use a smaller aperture with greater depth-of-focus (pretty shallow for macro) and the flash will stop action, allowing you to use a reasonable shutter speed. It can also cause the background to be dark, if you want that effect. I know of four options. The simplest is an ordinary flash off the camera, either on a special macro flash bracket (which can be almost as expensive as a macro flash!) or handheld. (On-camera flash will probably shoot over a subject that's very close to the lens.) You can use the Canon Off-Camera Cord with an E-TTL II-capable flash to get pretty good exposures, plus the Off-Camera Cord is useful for other situations. The cheapest "macro-only" approach is a cheap continuous "ring light." They aren't flashes, so they won't help stop action, but they can improve the light. Next are true ring flashes, including dedicated E-TTL-capable models. I use the Sigma EM-140 DG, as its specs (and use) are as good as the more expensive Canon MR-14EX and a lot better than the cheaper models from Bower, Phoenix, Dot Line, etc, though those would be much better than nothing. The "ultimate" is the Canon MT-24EX twin light, but it's also the most expensive, at nearly $700.
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